Stocks to Watch: Lululemon, Ciena, Facebook

Lululemon cut its sales guidance for the fiscal year as the yoga gear maker offered a cautious outlook for the current quarter, which includes the critical holiday shopping season. Shares slid 9.1% premarket to $62.10, despite Lululemon’s reporting stronger-than-expected results for its fiscal third quarter.

Social-media giant Facebook Inc., which has been public for less than two years, will join the Standard & Poor’s 500 index after the close of trading on Dec. 20. Facebook shares rose 3.8% to $51.23 premarket.

Fortis Inc. agreed to acquire UNS Energy Corp. for about $2.5 billion, as the Canadian utility moves to boost exposure within the U.S. by acquiring a firm with a presence in the U.S. southwest. Shares of UNS jumped 30% to $59.02 premarket.

Athenahealth Inc. shares tumbled 14% to $113.13 premarket as the provider of electronic health-care records released a muted outlook for the next fiscal year.

Vera Bradley Inc.'s fiscal third-quarter earnings fell 14% as the handbag designer recorded a drop in sales. The company also lowered its annual guidance again, with Chief Executive Robert Wallstrom citing recent trends. The news sent Vera Bradley’s shares down 8% at $20.95 premarket.

Roche Holding AG has entered a pact with Prothena Corp. PLC to develop and commercialize a treatment the clinical-stage biotechnology firm is developing for Parkinson’s disease. In after-hours trading, Prothena’s stock rose 8.6% to $29.75 premarket.

SunEdison Inc. said unit volumes in its semiconductor business are expected to be below prior expectations for the fourth quarter, due to continued market weakness, while pricing remains about flat. The chip and solar technology company also said it has decided to keep additional solar projects on its balance sheet in the fourth quarter rather than sell them, in order to retain more long-term project value. Shares slid 8.1% to $11.75 premarket.

ImmunoCellular Therapeutics Ltd. said its leading product candidate, a dendritic cell-based vaccine for brain cancer, didn’t show a statistically significant advantage in overall survival in a Phase II study. In a research note, Maxim Group said it is pushing its EU approval date target to 2019 and lowered its estimate on the stock to $12 a share from $18 a share. The stock plunged 62% to $1.04 premarket.

Aecom Technology Corp. on Wednesday said its current president, Michael S. Burke, would succeed John M. Dionisio as chief executive, part of a planned succession process at the engineering and infrastructure design firm.

American Airlines Group Inc. signed agreements with Bombardier Inc. and Embraer S/A (ERJ, EMBR3.BR) to purchase 90 new 76-seat regional jets, a multibillion-dollar order coming just after the airline completed its merger with US Airways Group Inc.

Centene Corp. agreed to acquire a roughly 68% interest in U.S. Medical Management LLC, a provider of in-home health services, for $200 million in cash and stock as the Medicaid insurer continues to expand its stable of services. Centene also said it is forming a new health-care enterprise holding company that will connect it and other health solution providers.

Chevron Corp. intends to spend $39.8 billion on capital and exploratory investments next year, about $2 billion less than is expected for 2013, which was a relative peak year for such spending.

Lpath Inc. said it is no longer actively seeking to reacquire exclusive rights to its leading product candidate from Pfizer Inc., saying the pharmaceutical giant informed the company that its offers weren’t competitive. The biotechnology company in October had warned that Pfizer might may divest itself of its exclusive option to co-develop the smaller firm’s leading product candidate–known as iSONEP.